[1] Univ Malaya, Dept Med, Fac Med, Kuala Lumpur 50603, Malaysia
[2] Univ Malaya, Dept Med, Med Ctr, Med, Kuala Lumpur 50603, Malaysia
[3] Univ Malaya, Clin Oncol Unit, Med Ctr, Oncol, Kuala Lumpur 50603, Malaysia
[4] Harvard Univ, Sch Med, Ctr Evaluat, Boston, MA USA